uniform mat4 transform;uniform mat4 modelview;uniform mat3 normalMatrix;attribute vec4 vertex;attribute vec3 normal;varying vec3 reflectDir;void main() {  gl_Position = transform * vertex;      vec3 ecNormal = normalize(normalMatrix * normal); // Vertex in eye coordinates  vec3 ecVertex = vec3(modelview * vertex); // Normal vector in eye coordinates  vec3 eyeDir = ecVertex.xyz;  reflectDir = reflect(eyeDir, ecNormal);}